Temperature-dependent growth window of CaTiO3 films grown by hybrid molecular beam epitaxy

Abstract

The authors report the effects of growth temperature on the self-regulated growth window of CaTiO3 thin films grown by hybrid molecular beam epitaxy (hMBE). Films were grown on (001) (La0.3Sr0.7)(Al0.65Ta0.35)O3 at temperatures between 700 and 950 °C. Calcium was supplied by a standard thermal effusion cell, while the metalorganic precursor titanium tetra-isopropoxide (TTIP) was used as the titanium source. The stoichiometric growth conditions were mapped using a combination of x-ray diffraction, reflection high energy electron diffraction, and atomic force microscopy. It is found that the growth window widened and shifted to higher TTIP fluxes with increasing temperature. Further, the shift of the growth window edge to Ti-rich conditions is three times larger than the growth window edge to Ca-rich conditions, which is discussed in general terms of the kinetic processes involved in hMBE.